A film forming processing using the ALD method which is one of CVD (Chemical Vapor Deposition) methods will be explained briefly.
The ALD method is a method in which two (or more) kinds of raw material gases used for forming a film are alternately supplied onto a substrate by one kind by one kind under certain film forming conditions (temperature, time and the like), the gases are allowed to be adsorbed by one atomic layer by one atomic layer, and a film is formed utilizing a surface reaction.
That is, when an Al2O3 (aluminum oxide) film is to be produced for example, a high quality film can be formed at a low temperature as low as 250 to 450° C. by alternately supplying TMA (Al(CH3)3, trimethyl aluminum) and O3(ozone) using the ALD method. In the ALD method, a film is formed by supplying a plurality of reaction gases alternately one kind by one kind in this manner. The thickness of the film is controlled by the number of cycles of the supply of the reaction gases. For example, when film forming speed is 1 Å/cycle in order to form a film of 20 Å, 20 cycles of the film forming processing are carried out.
A conventional ALD apparatus which forms the Al2O3 film is called a single wafer type apparatus in which the number of substrates to be processed in one processing furnace at a time is one to five, and an apparatus called a batch type apparatus in which 25 or more substrates are arranged in parallel to an axial direction of a reaction tube has not yet become commercially practical.
When an Al2O3 film is formed by such a vertical hatch type apparatus using TMA and O3, if a TMA nozzle and an O3 nozzle separately disposed vertically in the reaction furnace, there is an adverse possibility that TMA is decompose in the TMA gas nozzle and Al (aluminum) film is formed and if the film becomes thick, it is peeled off and becomes a foreign matter generating source.
It is a main object of the present invention to provide a substrate processing apparatus and a producing method of a semiconductor device capable of suppressing the generation of foreign matter caused by peel by preventing a film from being produced in a nozzle.